Lost mph @track???

[galoush]

Well i went out to the track Fri and i was quite disapointed Im starting to slip into my go with another motor idea again . The Mph was 106-108 from 111-113 . These are the changes from sig , ATR front mount from stck big neck, 275/60/15 from 275/50/15 , and 9-11 conv 3000 stall from 12inch 2400 nonlockup .It was cold around 45 from 80 s with a slight head wind from no wind at all . and full 225/60/15s fronts instead of drag skinny fronts . The 60 ft time did get a little better , with my 009injectors @25psi on C-16 i had the F.P up to 55psi Vac. off to keep the O2s from going into the mid 700s and seeing 1-2deg of knock when the F.P was @ 43psi , Looking back at the previous 113mph the O2s were 800mv. in 85 degree weather with the stock big neck . The chip is a Reds street chip with 21deg timming.Is this enough to knock 5mph off my previous times ?? I think its possible but ??? Maybe the motors getting tired i dont know its an all stock Longblock w/ about 100k valve spring included . Last summer i ran 12.49@113 . Well i guess going slow is better than blowing it up . 12.80s @ 107 were average with a 1.90 60ft average well at least i beat a 68-70s chevelle w/ slicks once on my first pass and once again on my last pass . My next move is S-10 rear cyl &soft shoes , slicks and pinion adj . I guess my 60 getting better with 5660s springs ., blistens , swaybar and full tires is good considering their not really "Drag Friendly" My G.F " Doe Eyes ( on this board) was there for moral support , no passes yet . The coolest run all day was a silver stock looking Z06 went high 9s on juice, that was

 

[galoush]

Only nine views , ANYBODY . What am i being blacklisted here .

 

[salvageV6]

Did you lock the converter?

Doe Eyes?

Maybe too rich also and the tire change and stock dead valve springs.....

I would think with C16 you could run 25 psi. boost and about 26* timing with no hint of KR.

We run 25 psi. with that timing or higher on pump gas and alky. using normal fuel pressures.

Get Eric Marshall to burn you a race chip.

Just my .02.

 

[galoush]

Didnt lock the convertor , im a little leary of that but i have done it in the past . I tried a Reds chip with 26deg timming and the car didnt seem to like it to much . Usually when i run 25 psi i get no knock but im guessing that with the street chip and high boost combined with the cooler weather and the frontmount may have leaned it out . Eric is turbotweek isnt he ? Thanks for the Feedback .

 

[WSLN 6]

You didn't lock the converter, so that's where some of your mph went. The looser your converter is, the more difference it will make when you lock it.
Maybe your cobo is a bit weak for those 28" tires as well....
Valve springs would also be a culprit.

 

[UNGN]

WAYYY too much fuel. 55 psi line of with 009's on a 12 second car is nuts. Did you mean 45 psi?

Don't fall into the trap of every time it knocks to raise the fuel pressure. Find out the real reason for the knock and fix it. Lack of fuel pressure didn't cause your knock. Turn the boost down to 22 with the high timing chip and you will run faster.

 

[galoush]

No i went up to 55 with the vac off , the O2 m.v were around 750s with 1-2 deg of knock , and when i went up with F.P it went away . Maybe i should have given it a chance . Maybe ill give the higher timming chip a try again with less boost , i thought that the extral boost would make more power than extra timming . How about the 28 inch tires ? UNGN i know your a big proponent of them but are they too much for my combo and that and the looser convertor combined would scrub off some Mph wouldnt it ?

 

[UNGN]

28" tires actually are EASIER for the motor to turn above 4400 RPM (the HP peak of a stock head motor) than at the same mph with 26" tires.

28" tires are supposed to cost 60 ft vs 26" tires because their gear reduction is less. Did your 60fts suffer with the 28"s?

55 PSI fuel pressure is not just nuts, but freakin nuts. If I was at the track with you, I would have thrown your FP gage over the fence if you told me you were running 55 psi line off. I'm surprised it even spooled.

The proper response to knock is first determine the cause, second, add octane (if maxed on octane, turn down boost) raising the FP is down the list a ways and then only in 1-2 psi increments (One to two and not twelve)

 

[galoush]

Yeah UNGN i should have lowered the boost a little , i was stuck in the ive run 25psi on the stock big neck I.C so its got to work with the ATR F.M mode , I actually ran about 26-27 psi which problibly didnt help alot when i had the F.P through the roof and that is most likely above the TA49s sweet spot on a stock headed motor. Looking at some other slips ive noticed another time i ran on a windy day the car Mphed @ 109-110 . The wind plus the looser convertor and the full fronts may have took away the extra Mph . I was running straight C-16 BTW . I cant see how the injectors could be running out of fuel , ive seen guys go 11s on blue tops . What about the street chip , i noticed on Reds chip pamphlet it says the 108 chip is for boost above 22psi due to extra fueling . I assume the street chips fuel curve may not be for high boost , i guess ill have to go back out and tune some more . The 60 foot was better but i also removed my pinion snubber before going to the track so i dont know if the 28s or the snubber or the convertor are the cause , but then again the front ends changed alot too so ill just try to maximize what ive got now i guess . One thing i noticed when i swaped the stock big neck out for the used ATR F.M is my boost was the same , so i guess my stocker was flowing the air ok , when i ran my best mph at the track i sprayed the stocker down with ice water from a garden sprayer , i guess that helped out alot too . I was hoping for more from the F.M which was part of my dissapiontment so oh well back to the drawing board i guess.

 

[XLR8]

Once when I was racing, my MPH started to decline and I was running lean per my O2. I kept adjusting FP to no avail. I swapped in a new O2 and my O2s went from 760 to 850! You might want to try a new O2.

 

[turbotwister]

throw that O2 out for god sake!

when are you people gonna learn that O2's are worthless for tuning.get yourself an EGT meter to tune it with.you will never look back.get your EGT'S in the 1600 range with no knock and you are flying.simple as that.

eric from turbotweak can make you a chip that will ignore the O2 for the most part so you can tune more acurately.contact him.you wont regret it.

nick,

 

[galoush]

Well the O2 was fairly new ( Denso ) and i did think that may give a different reading . As Far as the EGT goes i had a nice percys one a few years back and that puzzled me with some other issues causing problems so i figured it was not helping much , well ill get it sorted out one way or another . It gets confusing when you have a bunch of changes , and havent been to the track for a while . I was just thinking too i havent change my fuel filter in a while so thats next up on my to do list . Like tommorow.

 

[Quick6'n'-K.C.]

Originally posted by galoush
The chip is a Reds street chip with 21deg timming.Is this enough to knock 5mph off my previous times ??

YES.

get a race chip for that combo and you will go faster-